honestly though, not even 10% would be able to cash out completely without collapsing the prices.
10% of what? of total bitcoin amount? that is 1,670,000
BTC that is 9.2 billion dollar. if you dump that much money on ANY market, it will crash and burn to the ground. it is not just bitcoin.
besides, such crash and burn will be temporary. earlier this year, it was some bug or a whale's bot that went crazy and dumped bitcoin on an exchange and crashed price to $0.10. guess how many minutes that price lasted before going back up?